Pipe for watering plants

ABSTRACT

Pipe for watering plants, having an inner feed pipe (1) provided with orifices (5) and of substantially circular cross-section, on the outside surface of which there are one or a plurality of layers of fibrous material (2a, 2b). The feed pipe (1) and the layers of fibrous material covering at least the orifices (5) therein are enclosed by a casing (3) which is impervious to water and which has a longitudinal slit (4) disposed radially outside over the orifices (5) and through which the water, enriched with fertilizer if necessary, can pass into the soil under control.

This is a continuation of co-pending application Ser. No. 015,857 filedon Jan. 13, 1987 abandoned.

The invention relates to a pipe for watering plants, particularly forwatering the roots, comprising a feed pipe of substantially circularcross-section and incorporating orifices and on the outside surface ofwhich, at least in the region of the orifices, there is at least onelayer of fibrous material. The invention furthermore relates to a methodof producing a pipe for the watering of plants.

When watering plant roots, it is important to dispence the water assatisfactorily as possible as it emerges from the pipes laid in theground for watering purposes in order to prevent the soil becomingwaterlogged. At the same time, it is important to prevent the rootsgrowing into the watering pipe and the soil from damaging the pipe orclogging the orifices.

A watering pipe is already known (U.S. Pat. No. 3,302,408) wherein asynthetic plastics pipe provided with orifices is, for regulating theemergence of water, entirely enclosed in a layer of very fine glassfibres over which there is a synthetic plastics net, the entire pipebeing wrapped in and held together by a spiral of wire. However, thisknown pipe has the disadvantage that the external network of syntheticplastics can easily be damaged by stones in the soil or by a workingimplement. Furthermore, cutting it to specific lengths is verycomplicated due to the wire which is necessarily wound around it. Also asealing-tight connection of individual pipes, for example by fitting oneinto another, is possible only with difficulty.

In addition to this watering pipe of circular cross-section, there are amultiplicity of other watering pipes having complicated cross-sectionwhich likewise comprise porous or fibre-like coverings in order toregulate the emergence of water. This disadvantage of such pipes residesabove all in the expense of manufacture and in the fact that a tightconnection of pipes to one another or a sealing-tight connection to astorage tank, for example, can be very complicated.

Also known is a triple-shell watering pipe comprising an inner elasticand perforated feed pipe, a perforated outer pipe and, in between, alayer of fabric, the orifices in the inner feed pipe and the outer pipebeing staggered. In the case of this known pipe, the in most caseseasily dirtied water must flow in the direction of the fabric layer inorder to pass from an inner bore to an offset outer bore. Thus there isthe risk of the pipe becoming clogged with sludge. The known triplesheel pipe also has its disadvantages from the point of view ofmanufacture. In fact, making the outer orifices presents a difficultysince during the subsequent drilling of these orifices, it is quitelikely that the fabric underneath will also be damaged. If the orificesare already drilled into the outer pipe previously, then there is theproblem of pushing into the outer pipe the inner casing with its fabriccovering.

Therefore, the object of the invention is to provide a rugged andcompetitively priced pipe of the type mentioned at the outset in whichthe risk of clogging or siltation is largely reduced and which is easilymanufactured. Furthermore, it is intended to regulate the emergence ofwater which will be directed under control and also to prevent rootsgrowing into the interior of the pipe.

According to the invention, this is achieved in that a water imperviouscasing pipe is provided which consists preferably of synthetic plasticsmaterial and which is provided with at least one longitudinal slit andwhich substantially entirely encloses the feed pipe and the layer(s) offibrous material disposed thereon and in that the feed pipe has orificesonly in the region of the longitudinal slit in the enclosing casingpipe.

Where the pipe according to the invention is concerned, the water flowsthrough and at a right-angle to the surface of the layer(s) of fibrousmaterial. Slight siltation to which the present pipe is already lesssusceptible than the pipe in the citation can if necessary be forced outby a brief surge of water (a short period of over-pressure) so that thepipe can be cleaned.

The slit casing pipe furthermore safeguards adequately againstmechanical damage from outside the layer of fibrous material which isneeded for the measured emergence of water. By reason of thesubstantially circular cross-section of the pipe and the outer surfaceof the casing pipe which is closed except for the longitudinal slit, itis possible easily to achieve a sealing-tight connection or attachmentof the pipes.

A further advantage of the pipe according to the invention lies in thefact that the longitudinal slit which extends in the longitudinaldirection of the pipe allows of orientation of the pipe in connecting orattachment fittings. Also with regard to the cutting of pipes to length,this natural orientation of the cut lengths of pipe which establishesthe direction of water emergence is retained. It has in fact beendemonstrated that the orientation of the longitudinal slit is of greatimportance. For example, if the pipe is used for watering perennialplants, having the slit pointing downwardly can lastingly prevent theformation of algae.

So that the casing pipe is disposed concentrically in relation to theinner feed pipe, it is favourable according to a preferred feature ofthe invention for the feed pipe to be substantially completely encasedin one or a plurality of layers of fibrous material. Particularly ifthin layers of fibrous material are used, the layer of fibrous materialcan also be disposed only in the region of the longitudinal slit. Incertain circumstances, then, it may be advantageous for the casing andthe feed pipe to be welded, cross-linked or glued directly to each otherat those places where there is no longer any layer of fibrous materialbetween them.

It is preferably envisaged that the material of the casing pipe and/orof the feed pipe penetrate the layer(s) of fibrous material so that anintimate connection is possible between the layer of fibrous materialand the casing pipe or feed pipe and this will inter alia also pervent alayer of fibrous material being forced outwardly through thelongitudinal slit in the casing pipe due to the effect of the waterpressure in the feed pipe.

According to a further preferred feature of the invention, it isenvisaged that at least over a part of its inner surface which istowards the feed pipe, the casing pipe is welded, cross-linked or gluedto the feed pipe through the layer(s) of fibrous material so permittingof a secure connection between casing pipe and feed pipe. Furthermore,impregnated with glue or resin and then hardened out or permeated by thematerial of the welded-together casing and feed pipes, the layer offibrous material represents a reinforcing layer which imparts quiteconsiderable mechanical strength to the entire watering pipe.Preferably, the casing pipe and the feed pipe consist of thermoplasticssynthetic material. A reinforcing layer could then consist, for example,of a glass fibre fleece steeped in a epoxy resin.

A further preferred embodiment of the pipe according to the invention ischaracterized in that the casing pipe and/or the feed pipe is/are weldedto the layer(s) of thermoplastics synthetic material at least over apart of its/their surface which faces towards the layer of fibrousmaterial. Such a pipe can be produced particularly easily andinexpensively and yet it has an intimate connection between the casingand feed pipe on the one hand and the layer of fibrous material on theother.

A further preferred feature of the invention resides in the fact thatthe layer of fibrous material consists at least partially of anon-rotting material, for example synthetic plastic. Particularlysuitable are fine-mesh woven gauzes. Such a layer of fibrous materialpermits of adequate control of water emergence while permanentlypreventing penetration of roots. The risk of clogging is minimal.

A further preferred embodiment of the invention resides in that thecasing pipe is shrunk onto the feed pipe which is encased by thelayer(s) of fibrous material. In this case, the casing pipe and the feedpipe may each have axially extending and corresponding engaging means,for example a tongue and groove, establishing a form closure to preventthe two pipes rotating in respect of each other.

A further object of the invention is to provide a method of easilyproducing a pipe for watering and comprising a perforated feed pipe, aslotted casing pipe and at least one intermediate layer of fibrousmaterial.

According to the invention, this method is characterized in that thefeed pipe, which has a substantially circular cross-section, is extrudedin a first extruded and then, in a subsequent station, is prrovided withorifices and in that when the layer(s) of fibrous material, for examplewoven strips, is/are applied to the longitudinally moving feed pipe,whereupon, in a second extruder, the feed pipe and the fibre layer areenclosed by the casing pipe. Thus it is possible easily andinexpensively to produce an endless watering pipe which can then be cutto any desired length. It is advantageous thereby if the longitudinalslit in the casing pipe is already left exposed in the second extruder.

The invention will be explained in greater detail hereinafter withreference to examples of embodiment shown in the accompanying drawings.

FIG. 1 shows a diagrammatic perspective view of an embodiment of pipeaccording to the invention;

FIGS. 2 and 3 each show a cross-section through further embodiments ofthe pipe, and

FIG. 4 is a diagrammatic view of an apparatus for carrying out anexample of the method according to the invention whereby a watering pipecan be produced.

The pipe shown in FIG. 1 consists essentially of a feed pipe 1 ofthermoplastic synthetic material and provided with bores 5 and on theouter surface of which there are two layers 2a, 2b of fibrous materialconsisting of a non-rotting woven synthetic plastic material, and acasing pipe 3 of thermoplastic synthetic material provided with alongitudinal slit 4 and which is extruded, for example, onto the feedpipe 1 together with the layers 2a, 2b of fibrous material locatedthereon. With the exception of the longitudinal slit 4, the casing pipe3 lies rigidly all over on the layers 2a, 2b of fibrous materialproducing an extremely rugged watering pipe which is unaffected bymechanical stresses from outside caused possibly by relatively largestones or garden implements.

Emergence of water supplied through the feed pipe 1 and dischargethrough the longitudinal slit 4 in the casing pipe 3 and the bores 5underneath it and provided in the feed pipe 1 and which, according tothe invention, are disposed only in the region of the longitudinal slit4, is measured out by the layer 2b of fibrous material through which thewater passes substantially at a right-angle and which at the same timeprevents roots from growing into the interior of the feed pipe 1. Thelayer 2a of fibrous material shown underneath in FIG. 1 maintains thefeed pipe 1 concentrically in the casing pipe 3.

In the case of the embodiment of pipe shown in FIG. 2, the fibrematerial layer 2 consists of a glass fibre fleece into which thematerial of the thermoplastic casing pipe 3 and of the feed pipe 1 haspenetrated. Only in the region of the longitudinal slit 4 or the bores 5has no material penetrated the glass fibre fleece. Thus, the protectivecasing pipe 3 and the feed pipe 1 are on the one hand intimatelyconnected to each other via the fibre material layer 2 while on theother, the same fibre material layer 2 acts in the region of thelongitudinal slit 4 as a dispensing deevice to control the emergence ofwater and as a safeguard to prevent roots penetrating the pipe.

If both the casing pipe 3 andd also the feed pipe 1 consist ofthermoplastic synthetic material, then it is possible for both pipes 1,3 to be welded together. This welding process can take place through thefibre material layer 2, as is the case in the upper part of the pipeshown in FIG. 3, or directly between the two pipes 1, 3 if there is nointermediate layer of fibre material 2 (bottom part of the pipe shown inFIG. 3). If the fibre material layer is of a thermoplastic material,then this can even be welded at the same time. In any event, however,the fibre material layer 2 is retained in the region of the longitudinalslit 4 in the casing pipe 3.

According to the materials used, then in addition to welding of casingpipe and feed pipe, it is also possible for these to be cross-linked orglued to each other. Almost always, a layer of fibrous material which isimpregnated, for instance, with glue or resin (cross-linking medium) andwhich is then allowed to harden out, forms a reinforced layer whichenhances the mechanical strength of the pipe.

It goes without saying that the invention is not confined to the aboveembodiments of pipes. For example, it is also possible for the casingpipe to be shrunk onto the feed pipe and the layer(s) of fibrousmaterial. Furthermore, it is possible also to provide a plurality oflayers of fibrous material one on top of another. Furthermore, theorifices in the feed pipe and the longitudinal slits in the casing pipecan within the framework of the invention be differently constructedthan is shown on FIGS. 1 to 3.

FIG. 4 diagrammatically shows in arrangement for carrying out a methodaccording to the invention for producing a watering pipe. In a firstextruder 6, the feed pipe 1 which has a circular cross-section isextruded and then provided with orifices in a subsequent station 7.Then, strips of woven fabric rolled onto rollers 8 are applied to theperforated feed pipe 1 to serve as layers 2a, 2b of fibrous material. Inthis respect, according to the material used, it is possible to weld,cross-link or glue these layers 2a, 2b of fibrous material to the feedpipe 1. It is however also possible firstly just to apply the fabricstrips 2a, 2b to the feed pipe and to establish a rigid connectionbetween the casing pipe 3, the fibre material layers 2a, 2b and the feedpipe 1 only by means of the casing pipe 3 which is extruded on top. Inany event, the casing pipe 1 in the case of the present method isextruded in a second extruder 9, the longitudinal slit 4 over theorifices 5 in the feed pipe 1 being left exposed.

It is possible to use this method to produce endless watering pipes.Then, pipes can be cut to virtually any desired length. When they arelaid, these lengths of pipes can be easily and tightly fitted togetherby means of T-pieces or fit-in sleeves and can thus be easily adapted tothe sizes of the area to be watered.

We claim:
 1. A method for watering plants, particularly for watering the roots of plants which are buried in the soil, comprising:providing at least one section of a water feed pipe of substantially circular cross section with inner and outer surfaces and a longitudinal axis, said water feed pipe defining a region of a series of orifices enabling water to be forced through the feed pipe, said orifices being located on a parallel line to the longitudinal axis of the feed pipe; covering the orifices with a layer of water permeable fibrous material on the outer surface of the feed pipe; positioning the feed pipe with the fibrous material covering the orifices coaxially within a water imprevious casing pipe which defines at least one longitudinal slit, said casing pipe completely enclosing, except for the longitudinal slit, the feed pipe; orienting the casing pipe in such a way that said longitudinal slit, along the entire feed pipe, is located directly in line with the series of orifices of the water feed pipe; burying the casing pipe in the soil in relatively close proximity of the roots of the plants to be watered which the longitudinal slit of the casing pipe remains aligned with the series of orifices of the water feed pipe; and forcing pressurized water through said feed pipe so that the water flows along the entire feed pipe and out through said orifices to permeate said layer of fibrous material and flow through said longitudinal slit to provide a water supply to the surrounding soil and the roots of the plants to be watered; said alignment of the orifices of the water feed pipe with the longitudinal slit of the casing pipe providing easy orientation when connecting separate sections of pipe and reducing the risk of siltation by allowing for an easily regulated, straight line flow of water from the water feed pipe to the surrounding soil while allowing the layer of fibrous material to prevent roots and/or soil from entering the feed pipe.
 2. The method of claim 1 including the additional step of;increasing the pressure of the water over a short period of time to dislodge any foreign particles inhibiting flow thorugh the fibrous material or the longitudinal slit.
 3. The method of claim 1 wherein the casing pipe is buried in the soil so that the longitudinal slit of the casing pipe and consequently the orifices of the water feed pipe face downwardly so that when pressurized water is not being forced through the water feed pipe any residual water is driven by the force of gravity to flow through the orifices out of the water feed pipe thereby avoiding the build up of algae in the water feed pipe. 